This invention relates to a trigger control for an air powered tool.
The prior art is replete with examples of trigger controls for hand operated air powered tools. These trigger controls are generally meant to be operated by either the first or second finger of a hand. The structure and design of finger operated trigger controls have been such that substantial force and/or stroke length has been required to turn on the air supply to the power tool since the trigger button generally directly actuates the throttle valve controlling air flow to the tool motor. Trigger pull force may be 5 pounds or more and stroke length may be 0.200 inches or more. This has been true for those tools which utilize only an on and off air control and also those controls which have a control which enables one to continuously vary the air flow rate.
For most operators of these tools, the trigger control must be pulled with the distal segment of the first or second finger in order to pull the trigger button with the necessary force over its full stroke length. The combustion of substantial actuating force and/or stroke length can result in a number of problems for the operator due to the stresses on the operating finger. Most common of these problems is the disorder known as "trigger finger", a condition wherein the finger is locked at a right angle at the second joint. Other problems which have resulted include carpal tunnel syndome or tenosynovitis in the wrist and medial or lateral condylitis in the elbow. These stresses are most troublesome for those operators using hand operated air powered tools for long periods, for example, assembly line workers. A solution to this long standing problem has not been found in the art to this point.
It is therefore an object of the present invention to provide a trigger control for a hand operated air powered tool which reduces actuating finger stresses.
It is another object of the present invention to provide a trigger control for an air powered tool which has reduced actuating force.
It is a further object of the present invention to provide a trigger control for an air powered tool which has a short operating stroke.
It is yet another object of the present invention to provide an improved trigger control for an air powered tool which may continuously vary the air flow rate to the tool.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
A better understanding of the objects, advantages, features, properties and relations of the invention will be obtained from the following detailed description and accompanying drawings which set forth certain illustrative embodiments and are indicative of the various ways in which the principles of the invention are employed.